The new OEM LEDs are much better than than the non LEDs. I drove a 2015 for years and tried all kinds of LED replacements and while some were much better than the stock halogens, none were as good the OEMs in my 23.
I'm fairly certain the 5th is slightly larger in many ways. A few inches wider and taller, a little more passenger room and the rear cargo area is longer as well. I always felt my 4th was more car like in design than the previous and following generations. A 4 wheel drive station wagon.
I've owned 3 previous generations and I am now on my 2nd 5th gen (Limiteds) and in my opinion they have been the best size, most comfortable and best driving ones. I will say my 05 with the V8 was my absolute favorite as far as acceleration performance. I still miss that zip very much.